/*jslint adsafe: false, bitwise: true, browser: true, cap: false, css: false,
  debug: false, devel: true, eqeqeq: true, es5: false, evil: false,
  forin: false, fragment: false, immed: true, laxbreak: false, newcap: true,
  nomen: false, on: false, onevar: true, passfail: false, plusplus: true,
  regexp: false, rhino: true, safe: false, strict: false, sub: false,
  undef: true, white: false, widget: false, windows: false */
/*global jQuery: false, window: false */
//"use strict";

/*
 * Original code (c) 2010 Nick Galbreath
 * http://code.google.com/p/stringencoders/source/browse/#svn/trunk/javascript
 *
 * jQuery port (c) 2010 Carlo Zottmann
 * http://github.com/carlo/jquery-base64
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
*/

/* base64 encode/decode compatible with window.btoa/atob
 *
 * window.atob/btoa is a Firefox extension to convert binary data (the "b")
 * to base64 (ascii, the "a").
 *
 * It is also found in Safari and Chrome.  It is not available in IE.
 *
 * if (!window.btoa) window.btoa = $.base64.encode
 * if (!window.atob) window.atob = $.base64.decode
 *
 * The original spec's for atob/btoa are a bit lacking
 * https://developer.mozilla.org/en/DOM/window.atob
 * https://developer.mozilla.org/en/DOM/window.btoa
 *
 * window.btoa and $.base64.encode takes a string where charCodeAt is [0,255]
 * If any character is not [0,255], then an exception is thrown.
 *
 * window.atob and $.base64.decode take a base64-encoded string
 * If the input length is not a multiple of 4, or contains invalid characters
 *   then an exception is thrown.
 */

jQuery.base64 = (function ($) {

    var _PADCHAR = "=",
        _ALPHA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",
        _VERSION = "1.0";


    function _getbyte64(s, i) {
        // This is oddly fast, except on Chrome/V8.
        // Minimal or no improvement in performance by using a
        // object with properties mapping chars to value (eg. 'A': 0)

        var idx = _ALPHA.indexOf(s.charAt(i));

        if (idx === -1) {
            throw "Cannot decode base64";
        }

        return idx;
    }


    function _decode(s) {
        var pads = 0,
            i,
            b10,
            imax = s.length,
            x = [];

        s = String(s);

        if (imax === 0) {
            return s;
        }

        if (imax % 4 !== 0) {
            throw "Cannot decode base64";
        }

        if (s.charAt(imax - 1) === _PADCHAR) {
            pads = 1;

            if (s.charAt(imax - 2) === _PADCHAR) {
                pads = 2;
            }

            // either way, we want to ignore this last block
            imax -= 4;
        }

        for (i = 0; i < imax; i += 4) {
            b10 = (_getbyte64(s, i) << 18) | (_getbyte64(s, i + 1) << 12) | (_getbyte64(s, i + 2) << 6) | _getbyte64(s, i + 3);
            x.push(String.fromCharCode(b10 >> 16, (b10 >> 8) & 0xff, b10 & 0xff));
        }

        switch (pads) {
            case 1:
                b10 = (_getbyte64(s, i) << 18) | (_getbyte64(s, i + 1) << 12) | (_getbyte64(s, i + 2) << 6);
                x.push(String.fromCharCode(b10 >> 16, (b10 >> 8) & 0xff));
                break;

            case 2:
                b10 = (_getbyte64(s, i) << 18) | (_getbyte64(s, i + 1) << 12);
                x.push(String.fromCharCode(b10 >> 16));
                break;
        }

        return x.join("");
    }


    function _getbyte(s, i) {
        var x = s.charCodeAt(i);

        if (x > 255) {
            throw "INVALID_CHARACTER_ERR: DOM Exception 5";
        }

        return x;
    }


    function _encode(s) {
        if (arguments.length !== 1) {
            throw "SyntaxError: exactly one argument required";
        }

        s = String(s);

        var i,
            b10,
            x = [],
            imax = s.length - s.length % 3;

        if (s.length === 0) {
            return s;
        }

        for (i = 0; i < imax; i += 3) {
            b10 = (_getbyte(s, i) << 16) | (_getbyte(s, i + 1) << 8) | _getbyte(s, i + 2);
            x.push(_ALPHA.charAt(b10 >> 18));
            x.push(_ALPHA.charAt((b10 >> 12) & 0x3F));
            x.push(_ALPHA.charAt((b10 >> 6) & 0x3f));
            x.push(_ALPHA.charAt(b10 & 0x3f));
        }

        switch (s.length - imax) {
            case 1:
                b10 = _getbyte(s, i) << 16;
                x.push(_ALPHA.charAt(b10 >> 18) + _ALPHA.charAt((b10 >> 12) & 0x3F) + _PADCHAR + _PADCHAR);
                break;

            case 2:
                b10 = (_getbyte(s, i) << 16) | (_getbyte(s, i + 1) << 8);
                x.push(_ALPHA.charAt(b10 >> 18) + _ALPHA.charAt((b10 >> 12) & 0x3F) + _ALPHA.charAt((b10 >> 6) & 0x3f) + _PADCHAR);
                break;
        }

        return x.join("");
    }

    // private property
    var keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

    // private method for UTF-8 encoding
    function utf8Encode(string) {
        string = string.replace(/\r\n/g, "\n");
        var utftext = "";
        for (var n = 0; n < string.length; n++) {
            var c = string.charCodeAt(n);
            if (c < 128) {
                utftext += String.fromCharCode(c);
            }
            else if ((c > 127) && (c < 2048)) {
                utftext += String.fromCharCode((c >> 6) | 192);
                utftext += String.fromCharCode((c & 63) | 128);
            }
            else {
                utftext += String.fromCharCode((c >> 12) | 224);
                utftext += String.fromCharCode(((c >> 6) & 63) | 128);
                utftext += String.fromCharCode((c & 63) | 128);
            }
        }
        return utftext;
    }

    function encode(input) {
        var output = "";
        var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
        var i = 0;
        input = utf8Encode(input);
        while (i < input.length) {
            chr1 = input.charCodeAt(i++);
            chr2 = input.charCodeAt(i++);
            chr3 = input.charCodeAt(i++);
            enc1 = chr1 >> 2;
            enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
            enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
            enc4 = chr3 & 63;
            if (isNaN(chr2)) {
                enc3 = enc4 = 64;
            } else if (isNaN(chr3)) {
                enc4 = 64;
            }
            output = output +
                keyStr.charAt(enc1) + keyStr.charAt(enc2) +
                keyStr.charAt(enc3) + keyStr.charAt(enc4);
        }
        return output;
    }
    return {
        decode: _decode,
        encode: function (str) {
            return encode(str);
        },
        VERSION: _VERSION
    };

}(jQuery));

